It is the purpose of this project to seek a better understanding of the alterations in cellular and humoral parameters of immunological responsiveness associated with severe thermal injury. An attempt will be made to increase resistance to lethal effects of severe thermal injury by conditioning the host with agents capable of increasing reticuloendothelial system function. The unexpected detection of a large molecular size lipoprotein in the serum of burned mice, made possible by the utilization of ultra-high resolution density gradient electrophoresis techniques may, in addition, have provided a new approach to the isolation and characterization of neoantigen(s) and/or toxins produced in severe burns.